1. Field of the Invention
The present invention relates to an electronic timepiece configured to set and compute local time.
2. Description of the Related Art
In the related art, there has been known an electronic timepiece having a world time clock function of keeping information about respective time zones of the world, selecting an appropriate time zone in correspondence to acquired positional information and displaying dates and times (local times) of various regions of the world. In the electronic timepiece, positioning data and a city selected by a user operation are used as the positional information. Also, an electronic timepiece configured to keep implementation information of the daylight-saving time in addition to the information of the time zones and to automatically display the daylight-saving time during an implementation time period of the daylight-saving time in an implementation region of the daylight-saving time has been known. According to this electronic timepiece, when the positional information is once acquired, it is possible to display the correct local time without the user needing to check or adjust a setting relating to the local time, such as the time zone, whether the daylight-saving time is to be implemented, the implementation time period of the daylight-saving time and the like.
According to the electronic timepiece having the world time clock function, in order to correctly acquire the setting relating to the local time, it is necessary to associate and keep the positional information and the information about the time zone and the implementation region of the daylight-saving time. For example, JP-A-2009-180528 discloses a technology of dividing the world into geographically detailed blocks, keeping map data in which the time zone and the implementation region of the daylight-saving time are stored with being associated with the respective divided blocks, and enabling the correct local time corresponding to the time zone and the daylight-saving time over the world as well as the big city for which the time zone could be conventionally set.
However, the time zone setting of the world and the implementation setting of the daylight-saving time are frequently varied depending on political and religious situations, economic needs and the like. Most of the electronic timepieces, particularly, the portable timepieces have a limitation on a function of transmitting and receiving data to and from the outside, so that it is difficult to update the map data having a large size. Therefore, in a city and a region in which the local time setting information being kept has been changed, after the local time based on the old local time setting information is acquired or the user moves to another city or region, it is necessary for the user to correct the local time setting information each time.